We also introduce the notation
\(\Sigma ^\delta _\mathrm {res,fo,match}\)  (see also [1]}, [2]}) in order to
denote the results for the cumulative distribution for the (family of) flavour channel(s)
\(\delta \)  computed, with resummation, at fixed order, or matched between the two, respectively.
In the following, the channel label is omitted in general
expressions and we use the shorthand \(\sigma = \Sigma (1)\) . We denote the expansion of any
cumulative distribution \(\Sigma \)  to order \(\alpha _s^2\)  relative to the \(pp\rightarrow \mu ^+\mu ^-j\)  Born process as
\(\Sigma = \Sigma ^{(0)} + \Sigma ^{(1)} + \Sigma ^{(2)} + {\cal {O}}(\alpha _s^{4})\,,\hspace{28.45274pt} \Sigma ^{(k)} \propto \alpha ^2_\text{EW}\,\alpha _s^{1+k}\,.\) 
